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|Title:||A STUDY OF DIFFERENT FEM TECHNIQUES FOR MODELLING 3D METAL CUTTING PROCESS WITH AN EMPHASIZE ON ALE AND CEL FORMULATIONS|
|Keywords:||ALE;CEL;FEA;FEM;FINITE ELEMENT;ARBITRARY LAGRANGIAN EULERIAN;COUPLE EULERIAN LAGRANGIAN;METAL CUTTING;SIMULATION;ABAQUS;3D;METAL REMOVAL|
|Abstract:||Finite element(FE) method has been used to model cutting process since 1970s. However, it requires special techniques to cope with the difficulties in simulating extremely large strain when compare to static or small deformation problems. With the advancement of FE techniques, researchers can now have a deeper insight of the mechanism of material flow and chip formation of metal cutting process. Even the stagnation effect of the workpiece material in front of the cutting edge radius can be captured by using FE techniques such as Remeshing and Arbitrary Lagrangian Eulerian(ALE) formulation. However most of this models are limited to plane strain assumption which means they are 2-dimensional. Although 3D models are existing in the literatures, most of them employ Remeshing technique which is very computationally intensive and has many critics regarding its accuracy due to its frequent remeshing and mapping process. The rest of the 3D models employ Lagrangian formulation. The 3D models by Lagrangian formulation have the same limitations and drawbacks as in 2D models, as it requires failure criteria and in most of the cases predefined partition surfaces are also required. ALE technique on the other hand resolves all the drawbacks of the other formulations, it not only inherits the advantages of the other techniques but also has its own unique advantages such as it can simulate a longer time span up to couple seconds more economically by fixing the number of elements used. Although it's commonly accepted that ALE formulation is superior to other formulations of techniques in modeling metal cutting process, its usage is only limited to 2D models. Limited 3D ALE metal cutting models is available in the literature. Thus the main objective of this research is to explore the possibility of building a 3D metal cutting model with ALE formulation. The reliability and limitations will also be studied. Furthermore, Couple Eulerian-Lagrangian(CEL) formulation is a recent developed formulation that has a lot of potential in modeling metal cutting process in 3D. It will be compared with ALE models to study its potential and limitations in modeling metal cutting process. A new frictional model will also be proposed, which suggests that the frictional phenomenon in metal cutting is a consolidated effect of both friction between material interface and shear yield of the workpiece material. This idea provide a brand new perspective of viewing the friction phenomenon of metal cutting compared to those existed models.|
|Appears in Collections:||Open Access Dissertations and Theses|
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